DO NOT use steel wool on a stainless or aluminum gun.
The mild steel will embed tiny particles into the metal, and it'll rust later, damaging the gun metal.
I've had several cases of customers who steel wooled a stainless gun and were shocked when the gun suddenly developed a coating of rust.
For the same reason, never bead blast stainless or aluminum in a bead blaster that's been used to blast common steel.
The carbon steel in the media will embed into the stainless or aluminum and rust later.
If you want to restore a worn stainless guns finish, buy "ScotchBrite" pads or their equivalent at hardware store sandpaper sections, or from auto supply houses.
For deeper scratches, you can use the green synthetic pot scrubber pads from the grocery store, but the finer pads are a closer match to the original finish.
Simply use a pad to carefully rub out the scratch, (keeping in mind that very deep scratches AREN'T going to come out without a professional polishing job).
After you've removed light scratches and marrs, stroke the area in the same direction the original grain runs to blend it in with the rest of the area.
If the finish doesn't quite match, use a different "grit" pad that is a closer match.
Usually, most stainless guns can be matched with a #0000 equivalent pad.
Some cautions:
Don't use these pads to remove powder fouling and lead from cylinder faces. The pads ARE abrasive, and will round out the sharp edges of the chambers, ruining the cylinder.
The pads will ruin a bead blasted finish as used on the top strap. Don't use on bead blasted areas, and be careful not to "blur" the edges between bead blasted and satin finished areas.
The pads WILL get grit and dirt in the action and cylinder, so either be careful to keep it out, or clean the gun later to remove all foreign material.